Pistons for internal combustion engines



Dec. 23, 1958 J, BURNAND 2,865,694

PISTONS FOR INTERNAL COMBUSTION ENGINES Filed Nov. 1, 1956 5 Sheets-Sheet 1 FIG.|

f vsA/r-ak Jomv Bum/0 ND Dec. 23, 1958 Filed Nov. 1, 1956 J. BURNAND PISTONS FOR INTERNAL COMBUSTION ENGINES 3 Sheets-Sheet 2 I 4 msw rm: J50 BURN/9ND 2/ H W W M M firraRA/srs Unite 5.- Patent 2,865,694 V PISTONS FOR INTERNAL, COMBUSTION ENGINES John Burnand, Teddington, England A Application November 1, 1956, Serial No. 619,819

Claims priority, application Great Britain November 4, 1955 Claims. (Cl. 309-14) This invention is concerned with improvements in or relating to pistons for internal combustion engines.

Features and advantages of the present invention will appear from the following description of one embodiment of a piston given by way of example only, reference being had to the accompanying drawings in which:

Figure l is an elevation of a piston,

gigure 2 is a section on the line ll-II of Figure 1, an

Figure 3 is an underneath view.

The piston comprises a head 1, a main strut 2, an upper bearing 3, lower bearings 4 and a clampingring 5. The piston is intended primarily for use with a connecting rod 6 having integral therewith a gudgeon pin 7.

The upper bearing takes the form of a saddle received within a recess 8 in the strut and extends over substantially the whole of the top of the gudgeon pin. A key 9 engaging recesses in the strut and upper bearing is provided for locking the upper bearing.

Each of the lower bearings 4 is channelled and located under one arm of the gudgeon pin and each comprises an upstanding part of a semi-circular plate 11. Each plate 11 has a recess 12 on its straight edge, the recesses forming an aperture through which passes the connecting rod.

The plates 11 are retained in position by the clamping ring 5 which extends around flanges 13 on the underside of the plates.

From the head extends a skirt 14 into which the clamping ring is threaded, preferably a buttress thread being used. The skirt 14 permits heat to dissipate directly from the head during operation.

The strut may abut the head directly, but one or more distance plates 15 may be inserted between the head and the strut,-locating means being provided such as the recess 16 and boss 17 illustrated, a boss 18 and recess 19 being provided in the head and strut respectively.

The piston head has a sloping top surface so that it is urged under load to one side. On that side is provided a pad 20 backing upon a spherically headed bolt 21 mounted adjustably by nuts 22, 23 in a sprung plate 24 which has on three sides a flange 25 engaging a threesided boss 26 on the strut. The lower side of the boss is open to allow access to the nut 23. The pad has a curved upper and lower edge so that it will ride up on to the oil film on the cylinder wall. By loading of the piston towards one side and providing the pad the piston is caused to press hardest on that side where proper lubrication is assured by the pad.

The pad is held by a hook 27 on to a part of the skirt which is interrupted to receive thepad, so that a when the piston is removed from the cylinder the pad will not drop away.

The head and upper part of the skirt are of a smaller diameter than the cylinder so that the skirt is stepped as at 30. Around the part of reduced diameter one or 2,865,694 Patented Dec. 23, 1958 more piston rings are provided. In thisembodiment-are shown four L-sectionrings31, twoofiwhich, the lowest,

are-back-to-back; and between the, rings, are spacers 32,.

the whole being; clampedagainst ;the :step 3 .0 .by. the

and rings, may be applied to other forms of pistons such as the pistons described in my co-pending application No. 510,787 as may the provision of a spacer plate between the head and strut.

The strut provides the main support for the head and where a distance plate 15 is provided the locating means may comprise the boss and recess 16 and 18 for the upper face and an annular boss on the lower face engaging an annular recess in the strut the distance plate being provided for interruption of the direct flow of heat to the gudgeon pin.

The ring 33 is preferably locked against rotation with respect to the piston head and I prefer that the locking means should comprise a split pin passing at an angle from a recess in the ring 33, through that ring and through a part of the head. Also I prefer to provide recesses in the periphery of the ring 33 for engagement by a C- spanner so that the ring may be tightened down during assembly and so that the ring may be tightened down as and when the rings 31 and spacers 32 wear.

I claim:

1. A piston comprising a head having an upper part of smaller diameter than a lower part, a strut located beneath said head to support at least the central part of said head and being axially removable from said piston, upper bearing means associated with the underside of the said strut, removable lower bearing pieces, lower bearing retaining means making screw threaded engagement with a part carried by said head releasably clamping said strut between said head and said lower bearing means with said piston, a plurality of L-section rings surrounding said upper part of said head, and a clamping ring making screw threaded engagement with a threaded portion of said upper part.

2. A piston comprising a head, a strut located within said piston beneath said head to support at least the central part of said head and being axially removable from said piston, upper bearing means associated with the underside of said strut removable lower bearing pieces beneath said strut, lower bearing retaining means making screw threaded engagement with a part carried by said head releasably clamping said strut between said head and said lower bearing means within said piston, and a bearing pad carried by said strut for engagement with a cylinder wall.

3. A piston according to claim 2 including spacing means between said head and said strut.

4. A piston according to claim 2 in which the head is inclined with respect to the axis of said piston, the higher part of said head being to that side of said head beneath which is located said pad.

- 5. A piston comprising, in combination, a head having a sloping top surface inclined upwardly toward one side.

of said piston, a strut located within said piston beneath at least the central part of said head, said strut being axially removable from said piston, a spacer plate be tween'said head and said strut, upper bearing means associated with the under side of said strut, removable lower hearingpiecesdisposed-beneath said strut, lower bearing retaining means threadingly engaged with said head releasably clamping said strut between said head and said lower bearing means within said piston, and a bearing pad tt'ar'riecl by said strutsnbstantially coextensive with said one side-of said piston for engagement with a cylinder wall, said pad having a curved upper and lower edge for directing said pad upon an oil film disposed upon the cylinder wall.

- -References Cited in the file of this patent UNITED STATES PATENTS Smith Jan. 16, Freer May 18, Rodger Nov. 4,

FOREIGN PATENTS Great Britain Sept. 26, 

